Olivine (Mg,FE)2SiO4 is thought to be the most abundant mineral in the Earth's mantle above 410 km depth. At 410 km, olivine begins to transform to other structure which have the same chemistry but in which the atoms are packed more closely. These transformations have important consequences for a variety of Earth processes, therefore it is important for geophysicist to understand the mechanism and kinetics of these transformations in detail. This project involves studying one of these structural transformations in an analog system Mg2GeO4. Samples are partially transformed in a high pressure apparatus and then examined optically (in thin section with transmitted light) as well as with SEM (on polished, acid etched surfaces). In order to learn about the nature of the crystal defects produced in both phases during the transformation, TEM is required. The samples are examined both in normal imaging mode and in diffraction mode. Although conventional TEM can be used, HVEM is very desirable because thinning rates are different for the different phases and therefore foil thickness can be quite variable. Our laboratory has a Gatan Duo gun Argon ion mill and all of the other equipment needed for sample preparation with the exception of a carbon evaporator. I would like to use the HVEM to examine my samples on a steady basis, perhaps once or twice a month over the next few years.